832 
The palatine bones (22) are easily recog- 
nisable in Fishes, occupying the same place as 
in Serpents (fig. 439), and, moreover, further 
distinguished by being frequently armed with 
teeth which project into the roof of the mouth. 
In Reptiles, also, teeth are often attached to 
them where they assist in forming the cavity of 
the mouth. These bones are found in all the 
vertebrate classes. 
The transverse bones (24) occupy nearly the 
same situation in Fishes as in Reptiles, but in 
the latter they are most distinctly seen. In the 
Crocodile each is a bone of considerable size, 
composed of three branches and extending 
between the pterygoid bone and the junction of 
the jugal, the maxillary, and the posterior 
frontal. This bone is not met with, either in 
Birds or Mammalia, not even in the fetal 
period of their existence. 
The internal pterygoid ‘bones (25) are like- 
wise distinct in fishes, stretching between the 
Fig. 443. 
Shull of a young Ostrich ( Struthio Camelus ). 
eae bone and that which supports the 
ower jaw (26). In Reptiles they are large and 
im t detached bones, occupying the 
sition of the pterysoid of the sphe- 
noid ; but in Birds and Mammals they become 
completely anchylosed with the sphenoid, so 
that, by the human osteologist, they are erro- 
neously regarded as apophyses of that bone. 
OSSEOUS SYSTEM. (Comp. Anat.) 
Fig. 444. 
LE ‘ | 
a, 
Section of skull of young Ostrich. 
The zygomatic, Owen, (jugal, Cuvier,) are 
in Fishes broad pieces, generally of a ars r 
shape, placed behind the transverse, which by 
their inferior angle support the articulation 
of the lower jaw. In Reptiles, too, it may al- 
ways be distinguished by the latter cireum- 
stance, and in Serpents it is particularly re- 
markable (figs. 438, 439, 26), = 
from the squamo-temporal (mastoid, py) 
like a branch, and thus giving that extra 
dinary mobility to the articulation of the in 
ferior maxilla which enables those Reptiles” 
swallow prey so disproportioned to the size’ 
their mouths. In other Reptiles this mobili 
is in a great degree lost. But in Birds th 
zygomatic bones again assume very importa 
functions. They are here known by the nat 
ossa quadrata, and standing out to a ¢ 
siderable distance from the skull allow of gr 
mobility to the zygomato-maxillary articu 
and also to the bones supporting the supel 
maxilla. In Mammalia this zygomatie be 
is so firmly and undistinguishably unite 
the temporal that the human osteologist 
calls it the zygomatic process of that bone. 
The masto-temporal, Owen, ( Ci 
23), are in Fishes and Reptiles distinct elemet 
of the skull, which in the human cranium a 
consolidated with the other elements co 
posing the “ os temporis.” - 
